Preservation of proteinaceous materials and edible fibers spun therefrom

ABSTRACT

A process for preserving aqueous proteinaceous materials, e.g. soy flour, and the process of spinning edible fibers comprising the steps of: I. heating the proteinaceous material to a temperature of above 140* F. in aqueous slurry, and then II. treating a mixture of the heat-treated protein, a water soluble alginate and water with peroxide, III. adding carrageenin before or after heat treatment, and then IV. spinning the mixture into a coagulating bath, e.g. aqueous CaCl2.

atent Unite States Akinson [4 1 Feb. 29, 1972 [54] PRESERVATHON 0FPROTEINACEOUS MATERIALS AND EDIBLE FIBERS SPUN THEREFROM [72] Inventor:William T. Akinson, Minneapolis, Minn [73] Assignee: Archer DanielsMidland Company, Minneapolis, Minn.

[22] Filed: Feb. 7, 1969 [21] App]. No.: 797,668

52 U.S.Cl ..99/17,99/99,99/150 51 lnt.Cl ..-..A23j 1/14,A23l 1/20 58FieldoiSearch ..99/14,17,9s,99

[56] References Cited UNITED STATES PATENTS 2,930,700 3/1960 Bradof..99/99 Primary ExaminerA. Louis Monacell Assistant Examiner-WilliamAndrew Simons AttorneyPlumley, Tyner & Sandt [5 7] ABSTRACT A processfor preserving aqueous proteinaceous materials, e.g. soy flour, and theprocess of spinning edible fibers comprising the steps of:

aqueous CaCl 1 2 Claims, No Drawings PRESERVATION OF PROTEINACEOUSMATERIALS AND EDllBLE FIBERS SPUN THEREFROM in recent years,proteinaceous materials, especially those comprising soy flour and ametal alginate, have found increasing acceptance as foodstuffs for humanconsumption. In particular, these proteinaceous materials can be spun byextruding them through a spinnerette having a plurality of holes toproduce fibrous proteinaceous materials resembling meat, such as beef,pork, or chicken. Such spinning processes are described in Giddey, U.S.Pat. No. 2,947,644, and Ishler, U.S. Pat. No. 3,093,483. However,considerable difliculty has been experienced before, during, and afterspinning, due to the difficulty of preserving these proteinaceousmaterials and not permitting bacterial growth to occur. A number ofpreservatives and processes for preservation have been suggested;however, these suffer from one or more disadvantages, such as high cost,incomplete solubility of the preservative in the proteinaceous material,undesirable changes in taste and/or appearance of the proteinaceousmaterials, and hannful side effects due to the toxicity of certainpreservatives.

Accordingly, it is an object of the present invention to provide aprocess for preserving proteinaceous materials substantially free fromone or more of the disadvantages of prior processes. Another object isto provide a process which is inexpensive, employs a preservative whichis completely soluble in the proteinaceous materials, does not adverselyaffect taste or appearance, and is nontoxic to humans. Other objects andadvantages of the present invention will be apparent by reference to thefollowing detailed description thereof.

Briefly, the process of the present invention accomplishes thepreservation of proteinaceous materials by the steps of:

l. heating the proteinaceous material to a temperature above 140 F., and

I1. treating a mixture of the heat-treated protein, a water solublealginate, and water with peroxide.

The treated proteinaceous materials of this invention are especiallyuseful in the preparation of edible spun fibers. It is desirable toinclude carrageenin prior to spinning. Accordingly, the invention alsoinvolves the subsequent steps of:

ill. adding carrageenin to the protein-alginate mixture before or afterthe heat treatment step (I), and then IV. spinning the mixture into acoagulating bath.

Although any suitable means can be employed for heating theproteinaceous material, in a preferred embodiment the proteinaceousmaterial is mixed with water to form a slurry which is then admixed witha solution of the soluble alginate to form a mixture. This mixture isthen heated to a temperature above 140 F. and below the boiling point ofthe material, and preferably at a temperature of 140 F. to 180 F. Theheating is continued until the mixture no longer decomposes peroxide,which generally occurs after heating periods of from 5 to 60 minutes.Heating periods of about to 30 minutes have been found to besatisfactory and are preferred. Heating periods in excess of 4 hours areto be avoided because of resultant undesirable darkening of theproteinaceous materials and a reduction in toughness and tensilestrength. Conducting the heating step within the preferred temperaturerange and for the preferred time increases the tensile strength of thefibers. The protein can be heated separately if desired, and thealginate can then be added. It is important, however, that the alginateaddition be made before the peroxide treatment. In a preferredembodiment of the present invention, the heating step is effected bydirecting live steam into the proteinaceous materials until the desiredtemperature is reached. The proteinaceous materials can be maintained atthe desired temperature for the duration of the heating step byemploying small additional amounts of steam. The steam can be saturatedor superheated at pressures of 0 to 100 p.s.i.g., but saturated steam at0 to 20 p.s.i.g. is preferred for ease of handling. The peroxide can beadded at any convenient time after completion of the heating step andwhile the proteinaceous materials are still hot, or after theirtemperature has been reduced. However, it is preferably addedimmediately after the heating step for maximum preservation, andpreferably while the proteinaceous materials are still at a temperaturesubstantially equal to that of the heating step. The necessity of acooling step is thereby eliminated.

The process of the present invention is not limited to any particulartype of protein. Any type of edible protein of vegetable, fish, oranimal origin may be employed. The preferred proteins from thestandpoint of an optimum product are the oil seed proteins such aspeanut, cotton seed, sesame seed, or soybean proteins. The protein maybe employed in substantially pure or water-soluble form, or, as ispreferred, in the form of flakes or flour, generically herein referredto as meal, obtained on solvent extraction of oils and other fattymaterials. Solvent extraction of oil seeds to remove oil and other fattymaterials is well known in the art and thus need not specifically bedescribed. The proteincontaining oil seed meals which have proteinconcentrations of 40 to 70 percent are preferred.

The compositions utilized in the process of the present invention canhave widely varying weight ratios of protein to solublealginate, butthese ratios are generally between 1:100 and :1, and preferably between2:1 and 20:1. The water present in the mixture can comprise up to 95weight percent, based on the combined weight of protein, solublealginate, and water.

The peroxide is generally added as an aqueous solution. The peroxidesolution is added to the proteinaceous materials in amounts providing upto 2.0 and preferably 0.01 to 1.0 weight percent peroxide, based on thecombined weight of protein and soluble alginate.

The peroxide can be any water-soluble peroxide capable of decompositionto release oxygen in the presence of catalase. Inorganic peroxides,especially alkali metal peroxides such as sodium peroxide and potassiumperoxide, can be used. Hydrogen peroxide is especially preferred.

The soluble alginates useful in the present invention are generallythose having nontoxic monovalent anions, and preferably those ofammonium, potassium, or sodium, sodium alginate being the mostpreferred. Commercially available alginates are suitable for use in thepresent invention as disclosed in .the following examples.

Although it is not desired to limit the present invention to anyparticular theory, the following is offered by way of possibleexplanation to those skilled in the art. As a result of their normalmetabolic processes, bacteria produce enzymes such as peroxidase andcatalase. These enzymes decompose peroxide yielding nascent oxygen whichkills the bacteria. However, soy flour apparently contains a factorwhich decomposes peroxide. This factor, believed to be catalase, isheat-sensitive and can be denatured by heating it to temperatures aboveabout F. for 5 to 60 minutes. it has been found that, without this priorheating step, the peroxide is ineffective to preserve the proteinaceousmaterials. Other means for denaturing the catalase present in the soyflour would be expected to be equally effective if otherwise suitable.The necessity for the presence in the proteinaceous materials of anamount of the soluble alginate is not understood; however, it has beenfound that preservation by peroxide is ineffective in the absence of thealginate.

The bacteria-inhibited protein-alginate composition resulting from theabove-described process can be directly spun into edible fibers byextrusion of the composition into a coagulating bath in accordance withknown methods. The coagulating bath advantageously contains alkalineearth metal ion, preferably calcium ion, as disclosed in U.S. Pat. No.3,093,483 to Ishler, et al.

While the bacteria inhibited protein-alginate composition can bedirectly spun as described above, it has been found that the inclusionof small amounts of carrageenin improves the qualities of the ediblefiber. Accordingly, it is preferred that carrageenin be incorporatedinto the mix prior to spinning. The amount of carrageenin can varywidely but 0.1 to 10 weight percent based upon the total amount ofprotein-alginate-carrageenin present is preferred. The preferredproportions of carrageenin are from 1.0 to 5.0 weight percent calculatedas above.

The carrageenin can be added at any time prior to extrusion includingaddition prior to peroxide treatment.

The invention is further illustrated by the following examples in whichall parts and percentages are by weight unless otherwise indicated.These non-limiting examples are illustrative of certain embodimentsdesigned to teach those skilled in the art how to practice theinvention, and to represent the best mode contemplated for carrying outthe invention.

EXAMPLE 1 This example illustrates the preservation of proteins inaccordance with the process of this invention.

The following quantities of the following ingredients. are combined asindicated:

Item Ingredient Quantity A Soy Flour 5,400 g.

8 Water at 100 F. 15,750 ml.

C Sodium Alginate 5 I 8 g.

(Kelco HJ D Water at 212 F. 27,000 ml.

E Hydrogen Peroxide 98 ml.

(50 wt. 1: aqueous solution) F DYTOL (Rohm 8t Haas) 5 ml.

(60% Lauryl Alcohol),

EXAMPLE 2 This example illustrates the spinning of edible fibers fromthe bacteria inhibited protein-alginate composition of this invention.

The protein-alginate composition of Example I is extruded through aspinnerette having a plurality of holes into a coagulating solutioncomprising:

Item Ingredient Quantity CaCI,-2H,0 L005 g. Water [5,000 ml. HCI (37 wt.91: aqueous 75 ml.

solution) The ingredients are mixed together to form a coagulating bathhaving an initial pH of 1.3.

A hank of spun tow was washed in water before storage to preventhydrolysis of the fiber at low pI-Is. The washed fiber had apH of 3.8.

EXAMPLE 3 This example illustrates the spinning of edible fibers fromthe bacteria-inhibited protein-alginate composition of this in ventioncontaining added carrageenin.

To the protein-alginate composition of Example l 98 g. of carrageeninwas added and thoroughly mixed. The resulting composition was thenextruded into edible fibers in the manner described in Example 2.

EXAMPLE 4 This example illustrates protein preservation by the processof the present invention wherein carrageenin is added prior to peroxidetreatment.

The following quantities of the following ingredients are combined asindicated.

J Sodium Hydroxide (2.5 N:

l0 wt. aqueous solution) Items A, B, and C are thoroughly mixed in afirst vessel, and Items D and E are thoroughly mixed in a second vessel.The contents'of the first vessel are then poured into the second vesselto form an alginate/soy flour slurry having a temperature of F., whichis then heated to F. for about 10 minutes and held at that temperaturefor a period of 0-5 minutes. At the end of this period, F,G, and H areadded. Item I is then added, followed by Item J. The resultant mixturehas a viscosity of 6,000 c.p.s. and a pH of 7.8.

The mixture is deaerated by placing in a vacuum chamber and then spunthrough a spinnerette into a coagulating solution.

The coagulating solution is formulated from the following quantities ofthe following ingredients.

ltem Ingredient Quantity K CaCl,-2H,0 1,005 g. L Water 15,000 ml. M HCI(37 wt. aqueous 75 ml.

solution) Items K, L, and M are mixed together to form a coagulatingbath having an initial pH of 1.3.

A hank of spun tow was washed in water before storage to preventhydrolysis of the fiber at low pH. The washed fiber had a pH of 3.8.

EXAMPLE 5 This example illustrates the synthesis of a fibrous proteinproduct resembling chicken meat from the fibers of Example The followingquantities of the following ingredients are combined as indicated.

Ingredient The hank of Example 4 cut in 12 inch lengths was boiled 30minutes in 0.1 percent CaCl rinsed in cold water, dewatered anddeaerated in a centrifuge. Binder was buttered onto fibers and coatedfibers were pressed into greased Ham boiler. The

as in Example 1. The separate slurries were heat treated by heating to175 F. for 30 minutes and promptly cooled. The treated slurries werecombined as indicated in Table 11 below and tested by inoculation andincubation as in Example 6. The

boiler was closed under heavy pressure and product was 5 results aretabulated in Table ll and indicate that the therboiled for 30 minutes at15 p.s.i.g. The blo k was then molabile factor which inhibits peroxidepreservation is present refrigerated. Flavor and color were good. Thetexture was in soy flour but not alginate and that the presence ofalginate is slightly softer than straight alginate soy flour fiber.cessary for preservation of soy flour with peroxide.

TABLE II 0.1% Bacteria per gram Soy flour slurry Sodmm alginate slurryCombined hydrogen after E. coli peroxide Before Incubated 16 ExampleHeated Unheated Heated Unheated heating added added incubation hrs. at98.6 F.

ExXti/GLE 6 This example illustrates the protein preservation process ofthe present invention employing different conditions.

The procedure of Example 1 is repeated with the exception that times,temperatures, and conditions were varied as indicated below in Table I.The weight percent of hydrogen peroxide was based on the total systemincluding water, soy flour, and alginate. After hydrogen peroxidetreatment; bacterial counts were made, the samples were then inoculatedwith a culture E. coli. and incubated for 16 hours at 98.6 F. Afterincubation, another bacterial count was made to determine if the slurrysample was preserved by the treatment. In Example 6-15, catalase in theamount of 0.005 weight percent based on the total system (water, soyflour, and alginate) was added to the slurry after heating and beforeperoxide addition. The results are summarized in Table 1 below andindicate:

1. that the heat treatment is necessary to destroy the thermolabilefactor which interferes with the preservative effect of hydrogenperoxide;

2. that cooling prior to hydrogen peroxide addition is not necessary;

3. that catalase is the thcrrnolabile factor present in soy flour whichinterferes with the preservative effect of hydrogen peroxide; and

4. that the inoculum of E. coli. is not necessary to the opera- Althoughthe invention has been described in considerable 1. A process forpreserving aqueous proteinaceous materials, said process comprising thesteps of:

l. heating soy flour to a temperature above 140 F., for 5 to minutes,and then 11. treating a mixture of the heat-treated soy flour, a solublealginate, 0 to 10 weight percent of carrageenin based on said soy flouralginate-carrageenin mixture and water with a water-soluble peroxide;the weight ratio of soy flourzalginate being in the range of 1:100to100:1.

2. A process for inhibiting bacterial growth in an aqueous proteinaceousmixture comprising:

A. 1 to 100 parts soy flour containing naturally occurring amounts ofcatalase, and B. 1 to 100 parts soluble alginates, said processcomprising the steps of: l. denaturing the catalase, and then 11. addingwater-soluble peroxide proteinaceous materials. 3. A process forinhibiting bacterial growth in an aqueous to the aqueous tiveness of theprocess. mixture comprising 1 to 100 parts by weight soy flour and l toTABLE I 0.1% hydrogen Temperature Time of peroxide added to- Bacteriaper gram of heat heat treatment treatment E. coli Cold Hot Before AfterExperiment No. F.) (minutes) added slurry slurry incubation incubation5X10 98X10 78x10 16X10 lfiXlO 74 10 15 10 0 24x10 61 10 l5 10 10 1o 4510 48X10 25 10 0 78X10 72X10 12x10 66x10 11x10 14x10" 10 20 11X10 2X10"14 10 100 75 10 57 10 290 EXAMPLE 7 This example illustrates thenecessity of mixing alginate and protein prior to peroxide treatment andfurther shows that the heat labile factor is present in the soy proteinand not in the alginate.

Separate slurries of soy flour in water, and sodium alginate in water,respectively, were prepared using quantities so that when combined thefinal proportions of ingredients would be parts by weight solublealginates, said process comprising the steps of:

I. heating the soy protein alone or in the presence of alginate to atemperature from F. for 5 to 60 minutes up to F., and then 11. addingwater-soluble peroxide to said aqueous mixture.

4. The process of claim 3 wherein the peroxide is present in the mixturein an amount from about 0.01 to 1.0 weight percent, based on thecombined weight of soy flour and soluble alginate.

5. The process of claim 3 wherein the weight ratio of soy flourzsolublealginate is 2:1 to 20:1.

6. The process of claim 3 wherein the soluble alginate is sodiumalginate.

7. The process of claim 3 wherein the water-soluble peroxide is hydrogenperoxide.

8. The process of claim 3 wherein the water-soluble peroxide is added tothe aqueous proteinaceous materials while said materials are at atemperature substantially equal to that of the heating step.

9. The process of claim 3 wherein the heating of the aqueousproteinaceous materials is effected by contacting live steam with thematerials.

10. Aqueous proteinaceous materials which are hostile to 8 bacterialgrowth, comprising:

A. a soluble alginate, B. soy flour which has been heated to at least140 F. for at least 5 minutes, C. l to 10 weight percent of carrageenin,D. water, and E. up to 2.0 weight percent of water-soluble peroxidebased on the combined weight of A, B, and C; wherein the weight ratio ofAzB is 1:100 to :1. Ill. The material of claim 10 wherein C comprises0.] to 10 weight percent based on the weight of A, B, and C.

12. An edible food fiber comprising a coagulated fiber prepared from thecomposition of claim 11.

2. A process for inhibiting bacterial growth in an aqueOus proteinaceousmixture comprising: A. 1 to 100 parts soy flour containing naturallyoccurring amounts of catalase, and B. 1 to 100 parts soluble alginates,said process comprising the steps of: I. denaturing the catalase, andthen II. adding water-soluble peroxide to the aqueous proteinaceousmaterials.
 3. A process for inhibiting bacterial growth in an aqueousmixture comprising 1 to 100 parts by weight soy flour and 1 to 100 partsby weight soluble alginates, said process comprising the steps of: I.heating the soy protein alone or in the presence of alginate to atemperature from 140* F. for 5 to 60 minutes up to 180* F., and then II.adding water-soluble peroxide to said aqueous mixture.
 4. The process ofclaim 3 wherein the peroxide is present in the mixture in an amount fromabout 0.01 to 1.0 weight percent, based on the combined weight of soyflour and soluble alginate.
 5. The process of claim 3 wherein the weightratio of soy flour: soluble alginate is 2:1 to 20:1.
 6. The process ofclaim 3 wherein the soluble alginate is sodium alginate.
 7. The processof claim 3 wherein the water-soluble peroxide is hydrogen peroxide. 8.The process of claim 3 wherein the water-soluble peroxide is added tothe aqueous proteinaceous materials while said materials are at atemperature substantially equal to that of the heating step.
 9. Theprocess of claim 3 wherein the heating of the aqueous proteinaceousmaterials is effected by contacting live steam with the materials. 10.Aqueous proteinaceous materials which are hostile to bacterial growth,comprising: A. a soluble alginate, B. soy flour which has been heated toat least 140* F. for at least 5 minutes, C. 1 to 10 weight percent ofcarrageenin, D. water, and E. up to 2.0 weight percent of water-solubleperoxide based on the combined weight of A, B, and C; wherein the weightratio of A:B is 1:100 to 100:1.
 11. The material of claim 10 wherein Ccomprises 0.1 to 10 weight percent based on the weight of A, B, and C.12. An edible food fiber comprising a coagulated fiber prepared from thecomposition of claim 11.